Odyssey mission status Options

[OWW]

http://mars.jpl.nasa.gov/odyssey/newsroom/.../20070327a.html

Engineers for NASA's Mars Odyssey mission are examining data from the orbiter to determine whether onboard backup systems never used by the 6-year-old spacecraft could still be available if needed.

Odyssey reported last week that a power processing component of the backup, or "B-side," systems had stopped working. The component, the high-efficiency power supply, has a twin that is continuing to serve the "A-side" hardware, which is operating normally. Odyssey has stayed on its A-side systems, including the A-side flight computer, since launch on April 7, 2001. However, the A-side power supply cannot serve most systems on the B-side, including the backup B-side computer. If engineers do not determine a way to restore the B-side power supply, most of the backup hardware would not be available, if it were ever needed.

Odyssey is in its second extended mission. The orbiter is conducting scientific observations and also serving as the primary communications relay for NASA's Mars rovers. NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology, Pasadena, manages the Mars Odyssey Project for NASA's Science Mission Directorate, Washington. Lockheed Martin Space Systems, Denver, is the prime contractor for the project and built the spacecraft.


I hope Odyssey is not one failure away from another MGS-type loss because of this.

[Doug M.]

Hello all,

New member, first post. I have a few questions about Odyssey, and I'm hoping some of the well-informed members here will have answers!

1) What mission extension is Odyssey on? As far as I can tell, it had a fourth extension from 2010 to 2012. It should be on the fifth extension now, I suppose? Does anyone know if it is; and if so, until when does it run?

2) What's the current fuel supply? About when is it expected to run out?

3) Is fuel likely to be the limiting factor for Odyssey's lifespan?

4) What's the current status of Odyssey's various instruments? I know that MARIE (Mars Radiation Environment) has been dead since 2003, and another instrument has been inoperative. Is THEMIS the only instrument now operating?

5) I know that Odyssey is acting as a relay for MSL, of course. But I'm not up to speed on the details -- like, how often; how important is Odyssey's contribution; is it UHF only; how much can Odyssey buffer; things like that. (I am not asking anyone to sit down and write all that out! A link would be fine, if there's a page or paper somewhere explaining it.)

Many thanks in advance,


Doug M.

[Tom Tamlyn]

Doug M., welcome to the forum.

Those are interesting questions, but did you do any google searches of your own before you posted your wish list?

Googling "mars odyssey fourth mission extension," I found a mission timeline maintained by dmuller indicating that the third mission extension ended in September 2010. Refining the search to add the term "2010," I found a Universe Today article by Ken Kremer (mars loon) that answers most of your questions.

It would be a good idea to read the Rule and Guidelines for umsf.com.

[Doug M.]

Doug M., welcome to the forum.

Thanks! It's good to be here.

Those are interesting questions, but did you do any google searches of your own before you posted your wish list?

Yes, I did. A brief one, I admit, but I did. I found the Universe Today article -- it's a reference on Odyssey's wikipedia page.

Googling "mars odyssey fourth mission extension," I found a mission timeline maintained by dmuller indicating that the third mission extension ended in September 2010. Refining the search to add the term "2010," I found a Universe Today article by Ken Kremer (mars loon) that answers most of your questions.

The Muller timeline is not terribly helpful -- it's a brief listing of past events, and it gives a "predicted fuel exhaustion" of 2015, which is not consistent with other sources.

The Universe Today article is much better. However, it's two years old, and doesn't really answer my questions. For instance, it states that “More than 95 percent of the data from Spirit and Opportunity and approximately 79 percent of the data from Phoenix was relayed by Odyssey.” That's interesting, but it doesn't tell us anything about Odyssey's relationship with Curiosity. With regard to the fuel issue, the article says that “21.6 kg of propellant remains with an average consumption rate of about 1.4 kg per year... [however,] there are other elements of the spacecraft that might suggest that Odyssey’s life expectancy could be closer to six years. Lifetime issues are extremely difficult to estimate." That's some solid information, which is great. However, it doesn't tell us what the status is now, two years later. Has the fuel consumption stayed constant? Did the flywheel episode cost any fuel? Odyssey had to perform an unprecedented roll maneuver to gain signal from Curiosity; did that increase fuel consumption? Looking forward will the demands of communicating with two rovers require regular attitude changes; and if so, can this be done by flywheel, or will Odyssey have to burn more fuel?

It's entirely possible that this information is out there, and I'm just not googling hard enough! But to answer your question, yes I have made at least a basic online search; I wouldn't bring these questions here if I hadn't at least tried to find the answers first myself.

many thanks,


Doug

[stevesliva]

With regard to the fuel issue, the article says that “21.6 kg of propellant remains with an average consumption rate of about 1.4 kg per year... [however,] there are other elements of the spacecraft that might suggest that Odyssey’s life expectancy could be closer to six years. Lifetime issues are extremely difficult to estimate." That's some solid information, which is great. However, it doesn't tell us what the status is now, two years later. Has the fuel consumption stayed constant? Did the flywheel episode cost any fuel?

I read those lines with the same sort of thoughts as you-- they're pretty prescient. Perhaps they had something in mind like the reaction wheels when they said fuel might not be the limiting factor. And if Odyssey is like Mars Express, the safe mode certainly costs fuel.

Also, I was surprised with some googling how difficult it is to locate more mundane mission status reports for Odyssey, mostly because most of the search results are mirrors of the bigger NASA press releases. But they also might not really exist. Because it does sound like only THEMIS is working, perhaps meaning status reports would be rather useless without an anomaly. And the issue with the anomaly reports is that they're rather terse because they offer little rope for someone to hang them with.

[rlorenz]

I read those lines with the same sort of thoughts as you-- they're pretty prescient. Perhaps they had something in mind like the reaction wheels when they said fuel might not be the limiting factor.

....and sure enough, the 11/12/2012 status report at http://mars.jpl.nasa.gov/odyssey/ says they've just swapped to the B-side electronics string. I note the release says 'side swap was initiated last week in response to months of diagnostic data indicating that the A side's inertial measurement unit shows signs of wearing out. This gyroscope-containing mechanism senses changes in the spacecraft's orientation'... so it's the gyros rather than wheels this time.

There's a long history of (mechanical) gyros being the life-limiting element, especially on astronomy missions. But I thought current Mars spacecraft used IMUs with ring laser gyros (or maybe FOGs). Unless this is a sloppy release Odyssey must have been the last Mars mission to use mechanical gyros, or can RLGs/FOGs actually 'wear out' ?

[Doug M.]

There's a long history of (mechanical) gyros being the life-limiting element, especially on astronomy missions. But I thought current Mars spacecraft used IMUs with ring laser gyros (or maybe FOGs). Unless this is a sloppy release Odyssey must have been the last Mars mission to use mechanical gyros, or can RLGs/FOGs actually 'wear out' ?

Brief googling suggests that it's mechanical gyroscopes. Definitely doesn't seem to be a ring laser. Mars Odyssey was designed an built in the late 1990s, so that would make sense.

Mars Odyssey has been in space for eleven and a half years now, and orbiting Mars for over a decade. It's currently the third oldest continually active science mission, exceeded only by the two Voyagers. So, not really a surprise that various systems are starting to show signs of age. Hopefully it will last long enough for the next orbiter (MAVEN, fingers crossed) to come along.


Doug M.

[rlorenz]

Brief googling suggests that it's mechanical gyroscopes. Definitely doesn't seem to be a ring laser. Mars Odyssey was designed an built in the late 1990s, so that would make sense.

Did you find anything definitive ?
Ariane launchers were using RLGs in the early 1990s, if not before AFAIK, so it isnt a given that just because it was designed in the 1990s it had to use mechanical gyros...

Mars Odyssey has been in space for eleven and a half years now, and orbiting Mars for over a decade....... So, not really a surprise that various systems are starting to show signs of age.

I believe the MERs used Litton LN-200 IMU's, which have fiber optic gyros. But the datasheet for those says MTBF of >20,000 hrs, which means failures after a decade are certainly not ruled out (though that could just be a lower limit from lot testing, rather than
actual experience showing that failures occur after a mean period of 21,000hrs...)